Using internet and internet protocols to bypass PSTN, GSM map, and ANSI-41 networks for wireless telephone call delivery

ABSTRACT

A method and system to provide GSM subscribers roaming into CDMA or TDMA networks, and CDMA or TDMA subscribers roaming into GSM networks, with basic call delivery wireless services as long as the roamers can pay the bill with their valid credit card, and to do so independently of and as a bypass of GSM Memorandum of Understandings for cellular/PCS services. This is achieved by integrating the proper pieces of wireless and wireline networks and secure communications, using IP networks and protocols as an alternative to the existing telephony-based approach.

RELATED APPLICATIONS

This application is a continuation of provisional application serial No.60/154,501 filed Sep. 17, 1999.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

This invention relates to cellular call delivery services provided bycellular/PCS operators. Call delivery service permits a cellularsubscriber to receive phone calls either in a home network (e.g.,London) or while away from the home network (e.g., in Chicago).

Global Systems for Mobile Communications (GSM) is a widely popular TimeDivision Multiple Access (TDMA)-based standard used in Europe, China,selected parts of the United States, and other parts of the world. TDMAis a digital wireless technology.

A GSM subscriber who roams to Code Division Multiple Access (CDMA)wireless networks or other Time Division Multiple Access (TDMA) networksmay be denied wireless services even if the subscriber's mobile deviceis capable of multi-mode (TDMA, CDMA, or analog, and GSM) operation, andthe subscriber has the ability to pay for wireless calls with his/hervalid credit card. The basis for the denial of service is simply becausethere does not exist a GSM Memorandum of Understandings (MoU) betweenthe home GSM network and visited CDMA network for billing settlement.Similarly, a CDMA or TDMA subscriber who roams to GSM wireless networksmay be denied wireless services even if that subscriber's mobile deviceis also capable of multi-mode operation, where again the basis for thedenial of service is simply because there does not exist a GSMMemorandum of Understandings (MoU) between the home CDMA or TDMA networkand visited GSM network for billing settlement.

The existing infrastructure uses at least two disparate networks toimplement call delivery service to roaming wireless users. A firstnetwork is a control and signaling network that links authorizationcenters, billing centers, location tracking, and so forth. Examples ofcontrol networks include GSM MAP networks and ANSI-41 networks. A secondnetwork is a voice network that links calls from one location toanother. The Public Switched Telephony Network (PSTN) is one example ofa widespread voice network used to transmit calls from one location toanother. In the present practice, the control and signaling network isused to track the location of a mobile device, and when a call must bedelivered to the mobile device, the PSTN network is used to route thecall itself.

1. Field of the Invention

This invention relates to cellular telephony and the use of InternetProtocols and IP networks to replace traditional telephony setupinfrastructure for roaming cellular users. This invention also relatesto the field of providing mobile wireless telephone service for usersroaming outside their own predefined service area. This invention alsorelates to the field of interoperability of CDMA and GSM/TDMA cellularnetworks.

2. Description of Related Art

A GSM MoU is an agreement between a consortium of GSM wireless serviceproviders to coordinate billing settlement via a GSM MAP network. Forexample, a subscriber of a first GSM service provider may roam to aservice area controlled by a second GSM service provider. An establishedMoU allows the first GSM service provider to still serve the subscriberwhile that subscriber is in the service area corresponding to the secondGSM service provider. In practice, the second GSM service provider getspaid a portion of the service/roaming charge the first GSM serviceprovider charges the subscriber, which is one reason wireless “roamingcharges” are so expensive.

GSM MoU can also be used to coordinate billing settlement between GSMand CDMA (or TDMA) service providers. For example, a subscriber of a GSMservice provider may roam to a service area controlled by a CDMA serviceprovider. Assuming the user has a mobile device capable of multi-mode(in this example, GSM and CDMA) operation, an established MoU allows theGSM service provider to still serve the subscriber while that subscriberis in the service area corresponding to the CDMA service provider. Inpractice, the CDMA service provider gets paid a portion of theservice/roaming charge the GSM service provider charges the subscriber.

The Local Number Portability (LNP) feature could be used, to someextent, to bypass the lack of a GSM MoU. LNP allows a telephonesubscriber to “port” his/her phone number when that subscriber relocatesto a different region of the country, even when the local area code maybe different (e.g., a subscriber may reallocate from Chicago to NewYork, but still keep the original phone number used in Chicago that hasan area code of 312).

However, LNP updates are not dynamic by design and thus can have seriouslimitations. A subscriber who wants LNP typically will request thatservice by filling out a form. The phone company's administrative staffwill manually process the form and make necessary updates of variousdatabases to effect the requested LNP. Note that LNP is designed tosupport occasional change of location/re-location, and is typically donemanually; thus, there is a scalability issue in practice.

Public Switched Telephony Network (PSTN) refers to the public phonenetworks as we know them. PSTN is composed of switches and T1/E1 trunks,central office, etc. PSTN uses circuit-switched technology, in whichnecessary resources are allocated (dedicated) for the duration of aphone call. An IP network (e.g., the Internet), in contrast, is composedof nodes of computers, serves, routers, and communications links, etc.It employs packet-switching technology that decomposes data (e.g.,voice, web pages, an e-mail message) into IP packets. Each packet isthen transmitted over an IP network to a destination identified by an IPaddress and reassembled at the destination. An IP transmission iscompleted without pre-allocating resources from point to point.

H.323 is a (long) list of standards that supports “voice over Internet”(or voice over IP) and multimedia over Internet. As of the date of thisdisclosure, the URL databeam.com has further information on the H.323standards. H.323-based packet calls can bypass some portion of telephonyinfrastructure, but H.323 does not provide for mobility and radioresource usage is inefficient if IP packets are carried over the radiolink.

Mobile IP is described by Internet Engineering Task Force (IETF) Requestfor Comments (RFC) number 2002. As of the date of this disclosure, RFC2002 may be obtained from URL nic.mil/ftp/rfc/rfc2002.txt. Unlike H.323,Mobile IP does support packet mobility, but smooth handoffs—as smooth ascircuit cellular voice—are not supported.

One known commercial use of Mobile IP is deployed by Nextel, a wirelessservice provider. Using a cellular mobile phone by Motorola Corporationof Schaumburg, Ill., under the tradename iDEN 1000, Nextel allowssubscribers to access digital data from the Internet via Mobile IP.

The Diffie-Hellman algorithm is a math method allowing two parties toestablish a temporary secret for secure transmission of information.Reference: Diffie, W. and Hellman, M., “New directions in cryptography,”IEEE Transactions on Information Theory, Vol. IT-22, November 1976, pp.644-1654.

BRIEF SUMMARY OF THE INVENTION

This invention addresses the above issues of denial of service bycombining and integrating the proper pieces of circuit and packet, andthat of wireless and wireline. This invention provides a way to bypassSS7 networks, GSM MoU, IS-41, and PSTN so that GSM users roaming intoanalog, TDMA, or CDMA networks, and CDMA users roaming into GSM, TDMA,or analog networks, and TDMA users roaming into GSM, CDMA, or analognetworks, each having the ability to pay cellular calls with his/hercredit card, can be provided with basic call delivery cellular services.

These and other aspects and attributes of the present invention will bediscussed with reference to the following drawings and accompanyingspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents prior art, the typical infrastructure supporting callorigination and call delivery;

FIG. 2 represents an infrastructure supporting the first step of calldelivery in the present invention;

FIG. 3 represents an infrastructure supporting the second step of calldelivery in the present invention;

FIG. 4 represents an infrastructure supporting the third step of calldelivery in the present invention;

FIG. 5 illustrates a data structure supporting a mapping operation ofthe present invention in the visited wireless network;

FIG. 6 illustrates data structures in the user's mobile device utilizedby the present invention;

FIG. 7 illustrates a data structure supporting a mapping operation ofthe present invention in the voice and data service provider's network;and

FIG. 8 illustrates the bypass function of the Mobile IP tunnel of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawings, and will be described herein indetail, specific embodiments thereof with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the specific embodiments illustrated.

Cellular telephone users generally subscribe to a wireless serviceprovider. The subscriber may use their mobile devices within the homewireless network served by their wireless service provider in exchangefor subscription fees. However, users also may travel, and thus need tohave their mobile devices operate outside of their home wirelessnetworks as they visit other areas.

FIG. 1 shows a typical wireless infrastructure that providescellular/PCS services like call origination and call delivery for aroaming mobile device. For call delivery, the visited network 100 tracksthe location of a roaming user and the Visitors Location Register (VLR)120 reports that location information via a control network to the HomeLocation Register (HLR) 160 of the home network 150. Control networksmay include ANSI41 and GSM MAP types of networks. An AuthenticationCenter (AC) 170 in the home network 150 is used for user registrationand authentication, e.g., checking to see, among other things, if theuser has made payments. When a call 165 relayed from the Public SwitchedTelephony Network (PSTN) 180 to the home MSC 149 is to be delivered to asubscriber, the home Mobile Switching Center (MSC) 149 consults the HLR160 to determine the current whereabouts of the current VLR 120, and thecall is then directed via links 167 and the PSTN 180 to the visitedMobile Switching Center (MSC) 110 currently serving the mobile device.

An MSC is a telephone switch specialized for wireless and mobilitysupport. An MSC performs various functions, including mobilitymanagement, call handoffs, call admission, call control, resourceallocation, and so forth. The call is then relayed from the MSC 110 tobase stations 105 and via wireless communications 143 to the mobiledevice 140.

Since the visited network 100 and home network 150 may be operated bydifferent wireless operators, certain kinds of business roamingagreements are necessary for things like billing settlement. In GSMnetworks, a GSM Memorandum of Understanding (MoU) serves that purpose.In CDMA networks, an ANSI-41 roaming business agreement serves thatpurpose.

Table 1 summarizes the current cellular/PCS technologies and the networkelements that are involved in call origination and call delivery.

TABLE 1 Current Supporting Cellular/ Cellular Value Proposition PCSTechnologies Wireless and mobility Base stations, RF engineering, hardand soft handoffs Wide Coverage Area Automatic roaming across visitedand home wireless networks using VLR/HLR/AC US: ANSI-41 and businessroaming agreements GSM: GSM MAP and GSM Memorandum of UnderstandingsReliable services of both Call origination: involves VLR, HLR, andvoice/data call origination AC for service qualification, user servicevoice/data call delivery profile, and billing. Call delivery: involvesVLR and HLR for mobile location tracking, Temporary Local DirectoryNumber (TLDN) assignment, call forwarding/routing, and billing.

A problem occurs when a GSM user, who roams to a CDMA (or TDMA) network,may not be provided with cellular services because there lacks a GSMMemorandum of Understanding (MoU) between the home GSM network andvisited CDMA network. A similar problem occurs when a CDMA (or TDMA)user, who roams to a GSM network, may not be provided with cellularservices because there lacks a GSM Memorandum of Understanding (MoU)between the home CDMA (or TDMA) network and visited GSM network. This isso even when the user's mobile device is capable of multi-mode (TDMA,CDMA or analog, and GSM) operation and thus there is no technology,barrier, and the user has the ability to pay for cellular calls (e.g.,call delivery) with his/her valid credit card.

A CDMA (or TDMA) network typically is capable of CDMA and analog airinterfaces. Support of analog in the network (in addition to CDMA)allows the service provider to offer service and coverage toexisting/“old” analog cellular phones. A CDMA (or TDMA) mobile device orphone typically is capable of using both CDMA and analog air interfaces.Support of the analog air interface in the mobile device or phone allowsthe user to still have cellular service when that user roams to acellular network that supports only analog air interface, and in thecase where analog is the only interface compatible between the mobiledevice and the instant cellular network.

A GSM network typically does not support analog air interfaces,therefore a GSM user roaming to a CDMA (or TDMA) network will require amobile device that supports the GSM air interface and at least one ofCDMA (or TDMA) and analog air interfaces.

Similarly, for a CDMA (or TDMA) user roaming to a GSM network, the userwill require a mobile device that supports CDMA (or TDMA, respectively)air interfaces, possibly an analog air interface, plus a GSM airinterface.

For a TDMA user roaming to a CDMA network, and for a CDMA user roamingto a TDMA network, the mobile device must support the TDMA air interfaceand at least one of the CDMA and analog air interfaces.

The present invention combines the following technical components tobypass GSM MoU and PSTN for call delivery: (1) use of Mobile IP to trackthe location of mobile users; (2) use of H.323-based voice-over-IP totransport packet voice over Mobile IP tunnels; (3) use of H.323 serversin the visited network to convert packet voice to circuit voice; (4) useof the user's credit card as a payment method; and (5) use of theDiffie-Hellman algorithm to encrypt the user's credit card informationfor over-the-air transmission.

The use of H.323 servers in the visited network to convert packet voiceto circuit voice leverages the existing smooth handoffs capability ofcircuit cellular voice and the well-engineered CDMA/TDMA/GSMcircuit-mode air interface that provides superior efficiency of radioresource usage. The conversion also allows the roamer to receive calldelivery with an existing mobile device as opposed to having to purchasea new kind of “packet phone.”

A wireline/landline voice user can today use “voice-over-IP”, whichbypasses a PSTN, for voice service. Since the user's location is fixed,there is no such issue as user's location tracking (e.g. for calldelivery).

In contrast, for a wireless voice user who can be in a constant motion(e.g. moving from a coverage area associated with one visited wirelessnetwork to an adjacent/neighboring coverage area associated with adifferent visited network), the system must track the current locationof the user. Traditionally, location tracking for call delivery isthrough interactions between the VLR and HLR as shown in FIG. 1.

One reasonable summation of the present invention is, in a sense,“voice-over-Mobile-IP” for wireless voice users. Per Mobile IP standardsas referenced in RFC 2002, when a user moves to a different area, theuser's mobile device (capable of Mobile IP) will send, via a ForeignAgent (FA), Mobile IP registration/re-registration messages to theuser's Home Agent (HA), so the HA will know the whereabouts of the user(i.e. the FA that is currently serving the user). Thus the HA must trackthe IP address of the FA currently serving the roaming user.

Many of the same reference numbers are used in FIGS. 2 through 8 toidentify common features. It is to be understood that where the samenumber is used, it refers to the same feature in each of the drawings.

FIG. 2 shows the first step of call delivery, in one embodiment of thepresent invention, wherein prior to roaming, the mobile device 240 setsup call forwarding from the home wireless network 250 to a voice anddata service provider's network 252. The voice and data service providercan be an Internet service provider (ISP). The voice and data serviceprovider's network 252 comprises at least a home H.323 server 251 thatprovides a telephone number 242 to the user's mobile device 240 for callforwarding. The home H.323 server 251 also acts as Mobile IP home agent(HA) and provisions a Mobile IP shared secret 243 and the IP address 244of the HA into the user's mobile device 240.

Note that the provisioning of the Mobile IP shared secret 243 cannot bedone via wireless communication 256 with base stations 255, because theMobile IP shared secret will be revealed during such a transmission andwill no longer be a secret. Mobile IP shared secret provisioning can bedone through other means. In a preferred embodiment, when the usersubscribes to the voice and data service provider, the user will beinformed of the IP address 244 of the HA in the voice and data serviceprovider's network and the Mobile IP shared secret 243 assigned to him.This information may be accompanied with instructions how to enter thisinformation into the user's mobile device as part of the subscriptionsetup.

Home Agent (HA) and Foreign Agent (FA) are Mobile IP concepts andnetwork elements introduced in RFC 2002. Their functionality andoperation are described in detail in RFC 2002 and not detailed furtherherein.

FIG. 3 shows the second step of call delivery in one embodiment of thepresent invention, wherein the user's mobile device 240 is roaming in avisited wireless network 200. As the user powers on the mobile device240, the mobile device registers with the visited wireless network 200,which may be any type of wireless network including cellular or PCS.This registration permits the visited wireless network 200 to track themobile's location and perform call delivery, but does not implyconventional VLR 220/HLR 260 interaction. In the present invention, theroamer's HLR 260 and the roamer's AC 270 in the home wireless network250 are not contacted for call delivery. The registration conveys themobile device's International Mobile Subscriber Identifier (IMSI), theforwarding phone number 242 assigned by the voice and data serviceprovider, and the IP address 244 of the HA, and signature signed by theMobile IP shared secret 243 to the visited MSC 210 via the base stations205.

With the roamer's IMSI, forwarding number 242, and HA, IP address 244,the visited MSC 210 identifies the mobile device 240 as a special devicesupporting the present invention. This special identification aborts theconventional VLR/HLR interaction. The visited MSC and the mobile deviceinteract with each other to establish a temporary shared secret 245using the Diffie-Hellman algorithm. This mechanism is also used inCellular Digital Packet Data (CDPD) networks typically used for lowspeed packet data services. The user's credit card information istransmitted from the mobile device 240 to the visited wireless network200 via wireless communication with base stations 205 using theestablished temporary shared secret 245. The shared secret 245 permitsthe sensitive information of the user's credit card information to berelayed to the visited wireless network 200 securely.

The credit card information can be entered by the user on the mobiledevice keypad, or via a swipe of the card through a card reader slot onthe mobile device, or via some other means. In one embodiment, thecredit card information is optionally stored within the mobile device.In another embodiment, the credit card information must be entered bythe user for each use. In another embodiment, the user selects a creditcard number from a list to be used for the outgoing call. The creditcard number may belong to the user, the user's employer, or anotherthird party. The credit card number thus relayed securely is thenverified by the visited network's billing server to ensure it is valid,using methods familiar to anyone exposed to credit card payments andtransactions.

After credit card verification, the visited MSC 210 contacts the visitedH.323 server 211. The visited H.323 server 211 also acts as a Mobile IPForeign Agent (FA) which contacts the home H.323 server 251, via the HAIP address 244, to request an IP address to be assigned to the mobiledevice by home H.323 server 251 in the voice and data service provider'snetwork 252.

The request contains a signature so that the HA in the home H.323 server251 is able to authenticate the request by making sure that therequestor is indeed one of the subscribers of the voice and data serviceprovider's network 252. Signature authentication is required becauseotherwise it would be possible for a third party (attacker) tofraudulently impersonate the user's mobile device 240 and attempt torequest IP addresses again and again, potentially depleting the IPaddress pool managed by the home H.323 server 251 in the voice and dataservice provider's network 252.

In response to the request containing a signature, a dynamic IP address247 is allocated by the home H.323 server 251 which also provides DHCPservice.

DHCP is covered by RFC 2131. As of the date of this disclosure, RFC 2131may be obtained from URL http://nic.mil/ftp/rfc/rfc2131.txt. The majoruse of DHCP is to support dynamic IP address assignment For example, anISP (Internet Service Provider) can use DHCP to dynamically assign an IPaddress to a subscriber after he/she logs in over a dial-up connection;once the session is over, the IP address is recycled for other dial-inusers.

The dynamic IP address 247 from the home H.323 server 251 is relayedback to the FA of the visited H.323 server 211. The FA relays thedynamic IP address to the user's mobile device 240 during the IPConfiguration Protocol (IPCP) phase of Point-to-Point Protocol (PPP)initialization.

The mobile device initiates a Mobile IP registration request with the HAin the home H.323 server 251 via the FA in the visited H.323 server 211.The HA authenticates the request using the Mobile IP shared secret 243provisioned by the HA in the first step of the present invention, priorto the user roaming. Per the MD5 algorithm of Mobile IP, the Mobile IPregistration request from the mobile device is signed using theprovisioned Mobile IP shared secret 243, which permits verification ofboth message content and sender by the HA. A detailed technicaldiscussion of the MD5 algorithm may be located in RFC 2002 whichpertains to support of Mobile IP. Successful verification and receipt ofan acknowledgement response by the mobile device from the HA completesthe establishment of a Mobile IP tunnel 285.

Upon successful setup of the Mobile IP tunnel 285, the home H.323 server251 in the voice and data service provider's network 252 updates the HAmobility binding table 276 associated with Mobile IP and updates itsphone-number-to-IP-address table 275 that maps the user's forwardingphone number 242 provided by the home H.323 server 251 to the dynamic IPaddress 247 now assigned to the user's mobile device 240. The visitedH.323 server 211 in the visited wireless network 200 similarly updatesits IP-address-to-phone-number table 215 that maps the dynamic IPaddress 247 of the mobile to the forwarding phone number 242 provided bythe home H.323 server 251. When establishment of a Mobile IP tunnel 285is complete, the HA mobility binding table 276 is updated, and bothH.323 servers' tables 215, 275 are updated, the setup for the GSM MoUand the PSTN bypass of the present invention is complete.

The Mobile IP tunnel 285 is one example of bypassing the usualinteraction between the VLR and the HLR/AC, as well as bypassing thePSTN, both as used in the present invention. In a preferred embodiment,the Mobile IP tunnel is established within a public IP network such asthe Internet. In alternate embodiments, the Mobile IP tunnel may beestablished within a private IP network, or a combination of bothprivate networks and the public Internet. In another embodiment, theMobile IP tunnel may be layered on top of a different networkinfrastructure, in a manner consistent with current network practice.

An IP tunnel is a specific case of a general network tunnel, whichtypically has two ends, and encapsulates packets of a first protocol fortransmission from the first end to the second end of the tunnel using apotentially different second protocol for actual routing and delivery.Setting up a network tunnel generally involves a server or agent settingup each end prior to use. IP tunneling allows Internet standard-basedrouters to route IP packets from one end of a tunnel to the other end ofthe tunnel, regardless of the topology of the underlying IP network. Adetailed technical discussion of IP tunneling may be located in RFC 2002which pertains to support of Mobile IP.

FIG. 4 shows the last step of call delivery in one embodiment of thepresent invention. An incoming call 257 to the user is forwarded by thehome wireless network 250 to the forwarding phone number 242 associatedwith the home H.323 server 251. The home H.323 server 251 looks up thephone number 242 in its phone-number-to-IP-address table 275 and findsthe dynamic IP address 247 that has been assigned to the user's mobiledevice 240.

The home H.323 server 251 converts 283 the circuit call 257 to a packetcall (i.e., voice-over-IP) and forwards the packets to the HA. The HAforwards the packets over the Mobile IP tunnel 285 established in thesecond step to the FA in the visited H.323 server 211.

The visited H.323 server 211 in the visited wireless network 200 looksup the dynamic IP address 247 in its IP-address-to-phone-number table215 and finds the forwarding phone number 242 that has been assigned tothe user's mobile device 240 for roaming.

The FA in the visited H.323 server 211 converts 287 the packets receivedvia the Mobile IP tunnel 285 to a circuit call 286 and relays thecircuit call to the visited MSC 210. The visited MSC 210 forwards thecircuit call 286 on to the wireless base stations 205 for over-the-airtransmission to the user's mobile device 240.

In a preferred embodiment, both the conversions 283, 287 by H.323servers 251, 211 are performed in each of the respective home andvisited wireless provider's networks 250, 200, thus supporting speakingand listening by both the calling and called party. Specifically, thehome H.323 server 251 performs conversion 283 for circuit voiceoriginating from a call 257 to be conveyed via the Mobile IP tunnel 285,and performs conversion 287 for voice packet data conveyed via Mobile IPtunnel 285 from the user to be delivered as circuit voice to caller 257.Similarly, the visited H.323 server 211 performs conversion 283 forcircuit voice originating from the wireless connection with the basestations 205 to be conveyed via the Mobile IP tunnel 285, and performsconversion 287 for voice packet data conveyed via Mobile IP tunnel 285from the call 257 to be delivered via wireless communication from basestations 205 to the user's mobile device 240. In this embodiment, packetdata is conveyed via the Mobile IP tunnel 285, and is convertedappropriately to circuit calls by the H.323 servers 251, 211 at each endappropriately for interface to wireless (or in the case of the homewireless network 250, wireline) communications.

When the call is terminated, billing information is collected in thevisited network's billing server 290. The billing information mayinclude but is not limited to at least one of the duration of the call,which credit card number was used, identification of the IP tunnel, timeand date, and other kinds of billing data. At the end of a billingperiod, or when the accumulated bill amount exceeds some predeterminedamount, or when additional services or processing fees may be imposed,or at some other preferential time, the visited network's billing server290 interacts with the credit card's billing server 295 for billingsettlement, using the traditional and well-understood practices foraccounting for services rendered. In the present invention, the roamer'sHLR 260 and the roamer's AC 270 are not contacted for call delivery bythe VLR 220.

FIG. 5 illustrates a data structure supporting theIP-address-to-phone-number table 215 of the present invention in thevisited wireless network. The table 215 consists of associated pairs ofentries, wherein each line in the table contains one IP address and onephone number. A selected IP address 510 is used to index within the listof IP addresses 520 in the table, thus selecting a particular record orline 530. The corresponding phone number 540 in the line 530 is the dataretrieved from the table 215. The IP address 510 is said to “map to” theforwarding phone number 540, uniquely from the list of phone numbers 550in the table 215.

FIG. 6 illustrates data structures in the user's mobile device 240required for the present invention. One of the data structures is theInternational Mobile Subscriber Identifier (IMSI) 610 that uniquelyidentifies the user's mobile device. Provisioned into the mobile deviceby the voice and data service provider are the forwarding phone number242, the Mobile IP shared secret 243, and the IP address 244 of the HAin the home H.323 server. In the second step of the present invention,the temporary shared secret 245 is established within the mobile device240 to permit the sensitive information of the user's credit cardinformation to be relayed to the visited network securely. Credit cardinformation 620 may be stored within the user's mobile device, or it maybe entered by the user as required. The leased dynamic IP address 247 isused to establish the second end of the Mobile IP tunnel 285 as shown inFIG. 8.

FIG. 7 illustrates a data structure supporting thephone-number-to-IP-address table 275 as shown in FIGS. 3 and 4 of thepresent invention in the home wireless network. The table 275 consistsof associated pairs of entries, wherein each line in the table containsone phone number and one IP address. A selected phone number 710 is usedto index (within the list of phone numbers 720) in the table, thusselecting a particular record or line 730. The corresponding IP address740 in the line 730 is the data retrieved from the table 275. Theforwarding phone number 710 is said to “map to” the IP address 740,uniquely from the list of IP addresses 750 in the table 275.

FIG. 8 illustrates the bypass function of the Mobile IP tunnel of thepresent invention. The home MSC 253 in the home wireless network 250relays the inbound call 257 to the home H.323 server 251, which converts(283, 287) the call to packets that are conveyed via the IP tunnel 285.The packet data is converted (283, 287) back to circuit voice by thevisited H.323 server 211 and conveyed to the visited MSC 210 for overthe air transmission from the base stations 205 to the mobile device240. The normal interaction of the VLR and the HLR/AC is not used,effectively bypassing the network traditionally used for suchinteraction. The Public Switched Telephony Network (PSTN) astraditionally used to convey calls between wireless service providers(e.g., home wireless network 250 and visited wireless network 200 ofFIG. 4) is not used in the present invention, and is thus alsoeffectively bypassed. As a result, this invention provides for calldelivery to GSM subscribers who roam from their home GSM networks toCDMA networks, and call delivery to CDMA subscribers who roam from theirhome CDMA networks to GSM networks, by using IP tunnels to convey thecalls to be delivered.

The present invention includes a method to bypass Global Systems forMobile Communications (GSM) Memorandum of Understanding (MoU) to providebasic cellular call delivery service. The basic cellular call deliveryservice uses an Internet Protocol (IP) tunnel. The IP tunnel includes afirst end and a second end. A user having a mobile device subscribes toa home wireless service provider, and that provider serves a homewireless network in which the user can place and receive cellular calls.When that user travels outside of their home wireless network, they aresaid to be roaming.

When roaming, a user may be in an area served by a visited wirelessservice provider. The visited provider serves a visited wireless networkdistinct and separate from the home wireless network. In the situationwhere there does not exist a pre-arranged GSM MoU between the homewireless service provider and the visited wireless service provider theuser can still obtain basic call delivery service if the user has apayment means to pay for the basic visited wireless network calldelivery service.

A step in the preferred embodiment of the present method of theinvention has the user registering with a voice and data serviceprovider. This registration establishes the first end of the IP tunnel.This registration uses a home H.323 server in the voice and data serviceprovider's network. The home H.323 server in the voice and data serviceprovider's network is enhanced to further have the ability to provideHome Agent (HA) service.

Another step in the preferred embodiment of the present method of theinvention identifies the user's payment means to the visited wirelessservice provider. The typical payment means is a credit card, and thecredit card information must be securely transmitted from the user tothe visited wireless service provider. To securely transmit thisinformation, the mobile device and the visited wireless networkestablish a Diffie-Hellman temporary shared secret. With the secret inplace, the user's credit card information can be transmitted securely tothe visited wireless service provider, and upon receipt the visitedwireless service provider can verify the validity of the user's creditcard information.

Another step in the preferred embodiment of the present method of theinvention is to register with an H.323 server in the visited wirelessnetwork. The H.323 server in the visited wireless network further hasthe ability to provide Foreign Agent (FA) service. This registrationpermits the second end of the IP tunnel to be established to the user'smobile device.

Another step of the preferred embodiment of the present method of theinvention is to deliver calls to the user's mobile device, with thecalls being conveyed as data via the IP tunnel. As services are renderedto the user, billing information is compiled and collected by thevisited wireless service provider. The visited wireless service providerthen bills the user based on the billing information collected and theuser's credit card information.

The credit card information for the user can be stored within the mobiledevice by someone other than the user. Alternatively, it can be enteredby the user directly. In a preferred embodiment, the credit cardinformation is keyed into the mobile device. In another embodiment, thecredit card information can be scanned or swiped into the mobile deviceusing a card reader or similar apparatus.

The method of the present invention to establish the first end of the IPtunnel includes setting up call forwarding from the home wirelessnetwork to the voice and data service provider's network. This mayinvolve obtaining a telephone number for forwarding, and/or obtaining anIP address corresponding to the Home Agent (HA). Additionally, a MobileIP shared secret is set up with the voice and data service provider.

The method of the present invention to register with the visitedwireless network to establish the second end of the IP tunnel furtherincludes obtaining a dynamic IP address from the home H.323 server usingDHCP. This dynamic IP address is then relayed to the visited H.323server and then from the visited H.323 server via the visited wirelessnetwork to the user's mobile device. The user's mobile device canauthenticate the Mobile IP connection by using the Mobile IP sharedsecret and the response from the HA of the home H.323 server. Whencomplete and authenticated, the IP tunnel is established by the user'smobile device and then several tables are updated. These tables to beupdated include a phone-number-to-IP-address table in the home H.323server, a mobility binding table in the HA, and anIP-address-to-phone-number table in the visited H.323 server.

The method of the present invention to deliver calls to the user'smobile device via the IP tunnel further includes converting a circuitcall to packets by the home H.323 server. These packets are forwardedover the IP tunnel, reassembled at the far end by the visited H.323server, and then converted back into a circuit call for transmission tothe user's mobile device. The transmission occurs in the visitedwireless network. In a similar fashion to support bidirectionalcommunication typical of a telephone conversation, the visited wirelessnetwork receives transmissions from the user's mobile device as acircuit call. This call is then converted to packets by the visitedH.323 server. These packets are forwarded over the IP tunnel,reassembled at the far end by the home H.323 server, and then convertedback into a circuit call for eventual connection to the entity thatoriginally placed the call in the first place.

The method of the present invention to provide basic cellular calldelivery service for a user having a mobile device and subscribing to ahome wireless service provider serving a home wireless network is usedwhen the user roams to visit an area served by a visited wirelessservice provider serving a visited wireless network distinct andseparate from the home wireless network. If the user has a payment meansto pay for the basic cellular call delivery service, the method includesestablishing an Internet Protocol (IP) tunnel, having a first end and asecond end. This tunnel is used for conveying IP packets in bothdirections between the first end and the second end.

Calls are delivered to the user's mobile device via the IP tunnel.Billing information is collected from the visited wireless network bythe visited wireless service provider. The user is billed by the visitedwireless service provider responsive to the billing informationcollected and the user's identified payment means. Accordingly, theuser's payment means is identified to the visited wireless serviceprovider. Setup of the IP tunnel is started by registering with thevoice and data service provider to establish the first end of the IPtunnel at the HA within the voice and data service provider. Then theuser registers with the visited wireless service provider to establishthe second end of the IP tunnel at the FA.

The user's payment means may include credit card information. The stepof identifying the user's payment means to the visited wireless serviceprovider may include establishing a Diffie-Hellman temporary sharedsecret between the user's mobile device and the visited wirelessnetwork. The Diffie-Hellman temporary shared secret permits securelytransmitting the user's credit card information to the visited wirelessservice provider via the visited wireless network. The visited wirelessservice provider can then verify the validity of the user's credit cardinformation.

Registering with the user's home wireless service provider to establishthe first end of the IP tunnel within the voice and data serviceprovider's network may include setting up call forwarding from the homewireless network to the voice and data service provider's network. Itmay also include obtaining a Mobile IP shared secret from the voice anddata service provider. Call forwarding setup may or may not be performedin or within the home wireless network. Setting up call forwarding mayinclude obtaining a telephone number for call forwarding from the voiceand data service provider. It may also include providing a home H.323server by the voice and data service provider, and providing a HomeAgent (HA) function within the home H.323 server. Generally, the usermust obtain the IP address of the HA in the home H.323 server in thevoice and data service provider's network. This address may be storedwithin the user's mobile device.

The step of registering with the visited wireless service provider toestablish the second end of the IP tunnel may include providing avisited H.323 server in the visited wireless network. This visited H.323server generally provides a Foreign Agent (FA) function. Dynamic HostConfiguration Protocol (DHCP) in the voice and data service provider'snetwork is used to obtain a dynamic IP address. The dynamic IP addressis relayed from the HA via the visited wireless network to the user'smobile device. The user's mobile device authenticates the connectionusing the Mobile IP shared secret. Then the IP tunnel is established bythe user's mobile device, and a number of tables are updated, includinga phone-number-to-IP-address table in the home H.323 server, a mobilitybinding table in the HA, and an IP-address-to-phone-number table in thevisited H.323 server as previously disclosed.

The system of the present invention provides basic cellular calldelivery service via an Internet Protocol (IP) tunnel. The IP tunnel hasa first end and a second end. A user having a mobile device andsubscribing to a home wireless service provider serving a home wirelessnetwork can travel outside of the home wireless network. When the useris travelling within the boundaries of a visited wireless network, theuser is said to be roaming. If there does not exist a pre-arrangedGlobal Systems for Mobile Communications (GSM) Memorandum ofUnderstanding (MoU) between the home wireless service provider and avisited wireless service provider, the user can obtain basic calldelivery service if that user has a means to pay for that service.

The system of the present invention may include a payment identificationmeans for identifying the user's payment means to the visited wirelessservice provider. It also may include delivery service means forproviding basic cellular call delivery service via the IP tunnel,responsive to the payment identification means. The delivery servicemeans further may include a first end means to establish the first endof the IP tunnel within the home wireless network. The delivery servicemeans further may include a second end means to establish the second endof the IP tunnel in the visited wireless network. The delivery servicemeans further may include a circuit conversion means to convert circuitcalls to the mobile device to packets for conveyance via the IP tunnel.The delivery service means further may include a packet conversion meansto convert the packets conveyed by the IP tunnel to a circuit call. TheIP tunnel is established between a foreign agent and a home agent, andis generally transparent to the mobile device.

The system of the present invention may include a home H.323 server inthe voice and data service provider's network, and a visited H.323server in the visited wireless network. The home H.323 server mayinclude a phone-number-to-IP-address table and a mobility binding table.The visited H.323 server may include an IP-address-to-phone-numbertable. The system may include means to update the above disclosedtables, and any others that may be necessary.

The system of the present invention may include forwarding means forsetting up call forwarding from the home wireless network to a voice anddata service provider's network. The forwarding means is typicallyresponsive to the user's mobile device. The system may also includemobile shared secret means for obtaining a Mobile IP shared secret fromthe voice and data service provider's network. The mobile shared secretmeans is also typically responsive to the user's mobile device.Typically, a telephone number for call forwarding is provided by thevoice and data service provider responsive to the user's mobile device.Also, the IP address of the HA in the home H.323 server in the voice anddata service provider's network is provided to the user's mobile device.

The system of the present invention may include DHCP means for obtaininga dynamic IP address from the home H.323 server. Typically, the dynamicIP address is relayed from the home H.323 server via the visitedwireless network to the user's mobile device. The user's mobile devicemay then authenticate the connection by using the mobile shared secretmeans. Authenticating the connection permits an IP tunnel to beestablished. The system also monitors, collects, and compiles billinginformation in the visited wireless network for services rendered. Thisinformation can be used to bill the user's credit cards.

The system of the present invention can use credit card informationentered into the user's mobile device. This information may be enteredby other than the user. Alternatively, it can be keyed into the mobiledevice by the user for each use, or stored for a user selectable timeperiod. Another way to enter the information is for the user to scan orswipe a credit card in an appropriate reader apparatus in the mobiledevice. The user's payment information can be relayed securely to thevisited wireless service provider through the use of a Diffie-Hellmantemporary shared secret.

From the foregoing, it will be observed that numerous variations andmodifications may be effected without departing from the spirit andscope of the invention. It is to be understood that no limitation withrespect to the specific apparatus illustrated herein is intended orshould be inferred. It is, of course, intended to cover by the appendedclaims all such modifications as fall within the scope of the claims.

What is claimed is:
 1. A method to provide billing resolution and basicwireless call delivery service for a roaming user's mobile device,between a home wireless network supporting a home air interfacetechnology and a visited wireless network supporting a visited airinterface technology, the method comprising the steps of: providing ahome wireless network coupled to an existing Public Switched TelephonyNetwork (PSTN) and a signalling network comprising at least one of anexisting Global Systems for Mobile communication (GSM) MobileApplication Part (MAP) signalling network and an existing AmericanNational Standards Institute (ANSI-41) signalling network; redirectingcall delivery service for a user's mobile device from the home wirelessnetwork to a voice and data service provider's network that isindependent of the home wireless network, the signalling network, andthe visited wireless network; receiving redirection information from thevoice and data service provider's network and storing the receivedredirection information within the user's mobile device; relocating theuser's mobile device to a roaming area served by a visited wirelessnetwork; passing the redirection information and billing resolutioninformation from the user's mobile device to the visited wirelessnetwork; associating the user's mobile device with the visited wirelessnetwork; providing a first bypass network separate and distinct from theexisting signalling network and the existing PSTN network; communicatingthe association of the user's mobile device with the visited wirelessnetwork via the first bypass network to the voice and data serviceprovider's network; providing a second bypass network separate anddistinct from the existing signalling network and the existing PSTNnetwork; delivering at least one redirected call responsive to the voiceand data service provider's network via the second bypass network andvia the visited wireless network to the user's mobile device; andresolving billing for the wireless call delivery service responsive tothe billing resolution information.
 2. The method as in claim 1, whereinthe method is operational without requiring an existing GSM Memorandumof Understanding (MoU), and without requiring an existing ANSI-41business roaming agreement, and without using the existing PSTN for calldelivery from the voice and data service provider's network to thevisited wireless network, and without using the existing PSTN for calldelivery from the home wireless network to the visited wireless network,and without using the existing GSM MAP signalling network and withoutusing the existing ANSI-41 signalling network.
 3. The method as in claim1, wherein the step of passing the redirection information and billingresolution information from the user's mobile device to the visitedwireless network further comprises entering the billing resolutioninformation into the user's mobile device for each delivered call. 4.The method as in claim 1, wherein the redirection information comprisesat least a temporary Diffie-Hellman shared secret established betweenthe user's mobile device and the visited wireless network.
 5. The methodas in claim 1, wherein the GSM MAP network is a Signalling System 7(SS7) network.
 6. The method as in claim 1, wherein the ANSI-41 networkis a Signalling System 7 (SS7) network.
 7. The method as in claim 1,wherein the step of redirecting call delivery further comprisesproviding the home wireless network with a forwarding phone numbercorresponding to the voice and data service provider's network.
 8. Themethod as in claim 1, wherein the first bypass network is an InternetProtocol (IP) network.
 9. The method as in claim 1, wherein the firstbypass network and the second bypass network are the same bypassnetwork.
 10. The method as in claim 1, wherein the home air interfacetechnology comprises at least one of Time Division Multiple Access(TDMA), Code Division Multiple Access (CDMA), and Global Systems forMobile communications (GSM).
 11. The method as in claim 10, wherein thehome air interface technology additionally comprises an analog airinterface.
 12. The method as in claim 1, wherein the visited airinterface technology comprises at least one of Time Division MultipleAccess (TDMA), Code Division Multiple Access (CDMA), and Global Systemsfor Mobile communications (GSM).
 13. The method as in claim 12, whereinthe visited air interface technology additionally comprises an analogair interface.
 14. The method as in claim 1, wherein the home airinterface technology and the visited air interface technology eachcomprises at least one of Time Division Multiple Access (TDMA), CodeDivision Multiple Access (CDMA), and Global Systems for Mobilecommunications (GSM).
 15. The method as in claim 14, wherein the homeair interface technology and the visited air interface technology aredifferent and mutually exclusive.
 16. The method as in claim 15, whereinthe user's mobile device operates in at least two wireless modes, saidtwo modes corresponding respectively to the home air interfacetechnology and the visited air interface technology.
 17. The method asin claim 16, wherein the step of relocating the user's mobile device toa roaming area served by a visited wireless network further comprisesswitching the user's mobile device from operating in the wireless modecorresponding to the home air interface technology to the wireless modecorresponding to the visited air interface technology.
 18. The method asin claim 1, wherein the step of passing the redirection information fromthe roaming user's mobile device to the visited wireless network furthercomprises: arranging a temporary secure link between the user's mobiledevice and the visited wireless network, and using the temporary securelink to securely communicate the redirection information and billingresolution information from the user's mobile device to the visitedwireless network.
 19. The method as in claim 18, wherein the step ofarranging a temporary secure link further comprises establishing atemporary Diffie-Hellman shared secret shared by the user's mobiledevice and the visited wireless network.
 20. The method as in claim 19,wherein the billing resolution information identifies a credit card. 21.The method as in claim 20, wherein the step of passing the redirectioninformation and billing resolution information from the user's mobiledevice to the visited wireless network further comprises entering thecredit card identification into the user's mobile device.
 22. The methodas in claim 20, wherein the step of resolving billing further comprises:accumulating charges for call delivery services in a billing server; andreconciling accumulated charges for call delivery services with a creditcard billing server associated with the identified credit card.
 23. Themethod as in claim 1, wherein the second bypass network is an InternetProtocol (IP) network.
 24. The method as in claim 23, wherein theredirection information comprises at least an IP address of the voiceand data service provider's network, and wherein the step ofcommunicating the association further comprises contacting the voice anddata service provider's network via the IP network responsive to the IPaddress.
 25. The method as in claim 23, wherein the step of deliveringredirected calls further comprises: establishing an IP tunnel within thesecond bypass network, and delivering redirected calls from the voiceand data service provider's network via the IP tunnel in the secondbypass network to the visited wireless network.
 26. The method as inclaim 25, wherein the step of establishing an IP tunnel within thesecond bypass network further comprises communicating the IP address ofan end of the IP tunnel within the visited wireless network to the voiceand data service provider's network.
 27. The method as in claim 25,wherein the step of establishing an IP tunnel within the IP networkfurther comprises using Mobile IP protocol to track the varying locationof the user's mobile device.
 28. The method as in claim 25, wherein thestep of delivering redirected calls from the voice and data serviceprovider's network via the IP tunnel to the visited wireless networkfurther comprises: converting circuit calls at the voice and dataservice provider's network to packet data; conveying packet data via theIP tunnel to the visited wireless network; and converting packet data atthe visited wireless network to circuit calls.
 29. The method as inclaim 28, wherein the step of converting circuit calls at the voice anddata service provider's network further comprises encoding circuit callsinto packet data using H.323 protocol.
 30. The method as in claim 28,wherein the step of converting packet data at the visited wirelessnetwork further comprises decoding packet data into circuit calls usingH.323 protocol.
 31. The method as in claim 25, wherein the step ofdelivering redirected calls from the voice and data service provider'snetwork via the IP tunnel to the visited wireless network furthercomprises: converting circuit calls at the visited wireless network topacket data; conveying packet data via the IP tunnel to the voice anddata service provider's network; and converting packet data at the voiceand data service provider's network to circuit calls.
 32. The method asin claim 31, wherein the step of converting circuit calls at the visitedwireless network further comprises encoding circuit calls into packetdata using H.323 protocol.
 33. The method as in claim 31, wherein thestep of converting packet data at the voice and data service provider'snetwork further comprises decoding packet data into circuit calls usingH.323 protocol.
 34. A system to provide billing resolution and basicwireless call delivery service for a roaming user's mobile device,between a home wireless network and a visited wireless network, thesystem comprising: a user's mobile device, a home wireless network,coupled to both an existing Public Switched Telephony Network (PSTN) anda signalling network comprising at least one of an existing GlobalSystems for Mobile communication (GSM) Mobile Application Part (MAP)signalling network and an existing American National Standards Institute(ANSI-41) signalling network; a voice and data service provider'snetwork; redirecting call delivery means to redirect call deliveryservice from the home wireless network to the voice and data serviceprovider's network; a visited wireless network; and bypass network meanscoupling the visited wireless network and the voice and data serviceprovider's network, wherein the bypass network means is separate anddistinct from the existing signalling network and the existing PSTNnetwork; wherein the user's mobile device comprises at least: homewireless network operating means to provide for operating within thehome wireless network; visited wireless network operating means toprovide for operating within the visited wireless network; and storagemeans for storing redirection information; and wherein the visitedwireless network comprises association means for associating the user'smobile device with the visited wireless network and billing resolutionmeans for resolving billing for the wireless call delivery service. 35.The system as in claim 34, wherein the GSM MAP network is a SignallingSystem 7 (SS7) network.
 36. The system as in claim 34, wherein theANSI-41 network is a Signalling System 7 (SS7) network.
 37. The systemas in claim 34, wherein the system is operational without requiring anexisting GSM Memorandum of Understanding (MoU) and without requiring anexisting ANSI-41 business roaming agreement, and without using theexisting PSTN for call delivery from the voice and data serviceprovider's network to the visited wireless network, and without usingthe existing PSTN for call delivery from the home wireless network tothe visited wireless network, and without using the existing GSM MAPsignalling network and without using the existing ANSI-41 signallingnetwork.
 38. The system as in claim 34, wherein the home wirelessnetwork and the visited wireless network each comprise at least one of aTime Division Multiple Access (TDMA) wireless network, a Code DivisionMultiple Access (CDMA) wireless network, and a Global Systems for Mobilecommunications (GSM) wireless network, wherein the home wireless networkand the visited wireless network are different and mutually exclusive.39. The system as in claim 34, wherein the user's mobile device furthercomprises means to select between the home wireless network operatingmeans and the visited wireless network operating means.
 40. The systemas in claim 34, wherein the home wireless network is one of a TimeDivision Multiple Access (TDMA) wireless network, a Code DivisionMultiple Access (CDMA) wireless network, and a Global Systems for Mobilecommunications (GSM) wireless network.
 41. The system as in claim 40,wherein the home wireless network additionally comprises an analogwireless network.
 42. The system as in claim 34, wherein the visitedwireless network is one of a Time Division Multiple Access (TDMA)wireless network, a Code Division Multiple Access (CDMA) wirelessnetwork, and a Global Systems for Mobile communications (GSM) wirelessnetwork.
 43. The system as in claim 42, wherein the visited wirelessnetwork additionally comprises an analog wireless network.
 44. Thesystem as in claim 34, wherein the user's mobile device furthercomprises temporary secure link means to provide for securelycommunicating redirection information and billing resolution informationfrom the user's mobile device to the visited wireless network.
 45. Thesystem as in claim 44, wherein the temporary secure link means furthercomprises a Diffie-Hellman shared secret means for providing a temporaryDiffie-Hellman secret shared by the user's mobile device and the visitedwireless network.
 46. The system as in claim 44, wherein the billingresolution information identifies a credit card.
 47. The system as inclaim 46, wherein the user's mobile device further comprises means toenter the identification of the credit card.
 48. The system as in claim47, wherein the means to enter the identification of the credit cardcomprises a keypad.
 49. The system as in claim 47, wherein the means toenter the identification of the credit card comprises a credit cardreader.
 50. The system as in claim 47, wherein the billing resolutionmeans further comprises: a billing server for accumulating charges forcall delivery services; a credit card billing server comprising at leastan account associated with the identified credit card; and means toreconcile the accumulated charges for call delivery services against theaccount associated with the identified credit card.
 51. The system as inclaim 34, wherein the redirection information comprises at least atemporary Diffie-Hellman shared secret established between the user'smobile device and the visited wireless network.
 52. The system as inclaim 51, wherein the redirection information comprises at least an IPaddress of the voice and data service provider's network.
 53. The systemas in claim 34, wherein the bypass network is an Internet Protocol (IP)network.
 54. The system as in claim 53, wherein the IP network furthercomprises an IP tunnel.
 55. The system as in claim 34, wherein thebypass network further comprises an IP tunnel.
 56. The system as inclaim 55, wherein the IP tunnel is comprised of a first end within thevoice and data service provider's network, and a second end within thevisited wireless network.
 57. The system as in claim 55, wherein thevoice and data service provider's network further comprises Mobile IPmeans to track the varying location of the user's mobile device.
 58. Thesystem as in claim 55, wherein the voice and data service provider'snetwork further comprises: circuit call conversion means for convertingcircuit calls at the voice and data service provider's network to packetdata; and packet data conversion means for converting packet data at thevoice and data service provider's network to circuit calls.
 59. Thesystem as in claim 58, wherein the circuit call conversion means is anH.323 server.
 60. The system as in claim 58, wherein the packet dataconversion means is an H.323 server.
 61. The system as in claim 55,wherein the visited wireless network further comprises: circuit callconversion means for converting circuit calls at the visited wirelessnetwork to packet data; and packet data conversion means for convertingpacket data at the visited wireless network to circuit calls.
 62. Thesystem as in claim 61, wherein the circuit call conversion means is anH.323 server.
 63. The system as in claim 61, wherein the packet dataconversion means is an H.323 server.
 64. The system as in claim 56,wherein the first end further comprises a respective first end IPaddress, and the second end further comprises a respective second end IPaddress.